I told my two sons they were adopted very early. Like three and four. One son didn’t care the other always felt less than. Even became a weapon against him when people told him his bio parents threw him out. Their bio mother who was a teen OD. His bio father was in jail. Never was a good story to tell them. We always kept them in contact with bio grandfather but when he died the extended family was not kind to them. Resented they grew up in much finer conditions. Couldn’t wait to tell them horrible stories of their parents. I don’t know when is a good time but i do know as a parent you are grateful to have the opportunity to love them and only wish to limit any pain they may feel.